Today was close to 100° out and I just realized I hadn't cleaned my central air unit outside. I went outside, hosed it off, it really needed it! It had been having trouble keeping a cool temp. After cleaning it, it stopped running. The fan wouldn't spin at all. I thought I'd shorted something out, panic etc. Long story short, I changed the batteries and she's been running great for two hours. So if you think your system just can't keep up or is just not working properly, it might be something as simple as two double A's. #entertainment source